Intro

Sizing up younger, privately held firms is very tricky: Their fortunes can change very quickly, and they aren’t obliged to share their plans and finances with the public. With the help of CB Insights, a Manhattan-based research firm that tracks investment in high-growth private companies, we found 100 up-and-comers with serious growth potential. Seven of them shared their biggest mistakes, and how they dealt with them. For a full list of America’s 100 Most Promising Companies, go to www.forbes.com/ampc.